Base Station Assistance for Random Access Performance Improvement

1. A wireless transmit/receive unit (WTRU) comprising: a processor; and a transceiver, the processor and the transceiver are configured to acquire a first random access configuration and a second random access configuration, wherein the first random access configuration and the second random access configuration are different, and the processor and the transceiver are further configured to perform a first random access procedure using the first random access configuration using first physical resources and a second random access procedure using the second random access configuration using second physical resources, wherein the first random access configuration is used for at least initial random access and the second random access configuration is used for timing adjustments, wherein the first physical resources are different physical resources than the second physical resources, and the processor and the transceiver are further configured to receive a first message for the first random access procedure and to receive a second message for the second random access procedure, wherein the first message includes a single medium access control (MAC) header and a plurality of first random access responses and the second message includes a single MAC header and a plurality of second random access responses.

2. The WTRU of claim 1 , wherein the second random access configuration is used for periodic random access.

3. The WTRU of claim 1 , wherein the processor is further configured for each of the first message and the second message to identify one of the random access responses as being for the WTRU using a code indicated in the identified random access response.

4. The WTRU of claim 1 , wherein the first random access procedure is further used for handover random access.

5. The WTRU of claim 1 , wherein the second random access configuration is further used for power adjustments.

6. The WTRU of claim 1 , wherein the first random access configuration includes at least one random access code for use in the first random access procedure and the second random access configuration includes at least one random access code for use in the second random access procedure.

7. The WTRU of claim 1 , wherein the second random access procedure is for WTRUs that have been synchronized with a base station in the uplink.

8. The WTRU of claim 7 , wherein the first random access procedure is for WTRUs that have been synchronized with the base station in the downlink.

9. A method comprising: acquiring, by a wireless transmit/receive unit (WTRU), a first random access configuration and a second random access configuration, wherein the first random access configuration and the second random access configuration are different; and performing, by the WTRU, a first random access procedure using the first random access configuration using first physical resources and a second random access procedure using the second random access configuration using second physical resources, wherein the first random access configuration is used for at least initial random access and the second random access configuration is used for timing adjustments, wherein the first physical resources are different physical resources than the second physical resources, and receiving a first message for the first random access procedure and receiving a second message for the second random access procedure, wherein the first message includes a single medium access control (MAC) header and a plurality of first random access responses and the second message includes a single MAC header and a plurality of second random access responses.

10. The method of claim 9 , wherein the second random access configuration is used for periodic random access.

11. The method of claim 9 , further comprising identifying, for each of the first message and the second message, one of the random access responses as being for the WTRU using a code indicated in the identified random access response.

12. The method of claim 9 , wherein the first random access procedure is further used for handover random access.

13. The method of claim 9 , wherein the second random access configuration is further used for power adjustments.

14. The method of claim 9 , wherein the first random access configuration includes at least one random access code for use in the first random access procedure and the second random access configuration includes at least one random access code for use in the second random access procedure.

15. The method of claim 9 , wherein the second random access procedure is for WTRUs that have been synchronized with a base station in the uplink.

16. The method of claim 15 , wherein the first random access procedure is for WTRUs that have been synchronized with the base station in the downlink.